make StyleManager::CreateStylePreviewRenderer return std::unique_ptr

consequently fixing memory leak in sw/

Change-Id: Id66657cb8310baf42b0475cdef5e3618406974eb
Reviewed-on: https://gerrit.libreoffice.org/52842Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/sfx2/StyleManager.hxx

@@ -18,6 +18,7 @@
 #include <svl/style.hxx>
 
 #include <sfx2/objsh.hxx>
+#include <memory>
 
 namespace sfx2
 {
@@ -37,7 +38,7 @@ public:
 
     SfxStyleSheetBase* Search(const OUString& rStyleName, SfxStyleFamily eFamily);
 
-    virtual StylePreviewRenderer* CreateStylePreviewRenderer(
+    virtual std::unique_ptr<StylePreviewRenderer> CreateStylePreviewRenderer(
                     OutputDevice& rOutputDev, SfxStyleSheetBase* pStyle,
                     long nMaxHeight) = 0;
 };

include/svx/CommonStyleManager.hxx

@@ -28,7 +28,7 @@ public:
         : StyleManager(rShell)
     {}
 
-    virtual sfx2::StylePreviewRenderer* CreateStylePreviewRenderer(
+    virtual std::unique_ptr<sfx2::StylePreviewRenderer> CreateStylePreviewRenderer(
                                             OutputDevice& rOutputDev, SfxStyleSheetBase* pStyle,
                                             long nMaxHeight) override;
 };

svx/source/styles/CommonStyleManager.cxx

@@ -14,11 +14,11 @@
 namespace svx
 {
 
-sfx2::StylePreviewRenderer* CommonStyleManager::CreateStylePreviewRenderer(
+std::unique_ptr<sfx2::StylePreviewRenderer> CommonStyleManager::CreateStylePreviewRenderer(
                                             OutputDevice& rOutputDev, SfxStyleSheetBase* pStyle,
                                             long nMaxHeight)
 {
-    return new CommonStylePreviewRenderer(mrShell, rOutputDev, pStyle, nMaxHeight);
+    return std::unique_ptr<sfx2::StylePreviewRenderer>(new CommonStylePreviewRenderer(mrShell, rOutputDev, pStyle, nMaxHeight));
 }
 
 } // end svx namespace

sw/source/uibase/sidebar/StylePresetsPanel.cxx

@@ -49,8 +49,8 @@ void renderPreview(sfx2::StyleManager* pStyleManager, OutputDevice& aOutputDevic
 
     if (pStyleSheet)
     {
-        sfx2::StylePreviewRenderer* pStylePreviewRenderer;
-        pStylePreviewRenderer = pStyleManager->CreateStylePreviewRenderer(aOutputDevice, pStyleSheet, nHeight);
+        std::unique_ptr<sfx2::StylePreviewRenderer> pStylePreviewRenderer
+            = pStyleManager->CreateStylePreviewRenderer(aOutputDevice, pStyleSheet, nHeight);
         pStylePreviewRenderer->recalculate();
         pStylePreviewRenderer->render(aRect, sfx2::StylePreviewRenderer::RenderAlign::TOP);
     }